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1 : /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 : /* vim:set ts=2 sw=2 sts=2 et cindent: */
3 : /* This Source Code Form is subject to the terms of the Mozilla Public
4 : * License, v. 2.0. If a copy of the MPL was not distributed with this
5 : * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6 :
7 : /**
8 : * The IterableIterator class is used for WebIDL interfaces that have a
9 : * iterable<> member defined with two types (so a pair iterator). It handles
10 : * the ES6 Iterator-like functions that are generated for the iterable
11 : * interface.
12 : *
13 : * For iterable interfaces with a pair iterator, the implementation class will
14 : * need to implement these two functions:
15 : *
16 : * - size_t GetIterableLength()
17 : * - Returns the number of elements available to iterate over
18 : * - [type] GetValueAtIndex(size_t index)
19 : * - Returns the value at the requested index.
20 : * - [type] GetKeyAtIndex(size_t index)
21 : * - Returns the key at the requested index
22 : *
23 : * Examples of iterable interface implementations can be found in the bindings
24 : * test directory.
25 : */
26 :
27 : #ifndef mozilla_dom_IterableIterator_h
28 : #define mozilla_dom_IterableIterator_h
29 :
30 : #include "nsISupports.h"
31 : #include "nsWrapperCache.h"
32 : #include "nsPIDOMWindow.h"
33 : #include "nsCOMPtr.h"
34 : #include "mozilla/dom/ToJSValue.h"
35 : #include "jswrapper.h"
36 : #include "mozilla/dom/IterableIteratorBinding.h"
37 :
38 : namespace mozilla {
39 : namespace dom {
40 :
41 : class IterableIteratorBase : public nsISupports
42 : {
43 : public:
44 : NS_DECL_CYCLE_COLLECTING_ISUPPORTS
45 0 : NS_DECL_CYCLE_COLLECTION_CLASS(IterableIteratorBase)
46 : typedef enum {
47 : Keys = 0,
48 : Values,
49 : Entries
50 : } IterableIteratorType;
51 :
52 0 : IterableIteratorBase() {}
53 :
54 : protected:
55 0 : virtual ~IterableIteratorBase() {}
56 : virtual void UnlinkHelper() = 0;
57 : virtual void TraverseHelper(nsCycleCollectionTraversalCallback& cb) = 0;
58 : };
59 :
60 : template <typename T>
61 : class IterableIterator final : public IterableIteratorBase
62 : {
63 : public:
64 : typedef bool (*WrapFunc)(JSContext* aCx,
65 : IterableIterator<T>* aObject,
66 : JS::Handle<JSObject*> aGivenProto,
67 : JS::MutableHandle<JSObject*> aReflector);
68 :
69 0 : explicit IterableIterator(T* aIterableObj,
70 : IterableIteratorType aIteratorType,
71 : WrapFunc aWrapFunc)
72 : : mIterableObj(aIterableObj)
73 : , mIteratorType(aIteratorType)
74 : , mWrapFunc(aWrapFunc)
75 0 : , mIndex(0)
76 : {
77 0 : MOZ_ASSERT(mIterableObj);
78 0 : MOZ_ASSERT(mWrapFunc);
79 0 : }
80 :
81 : void
82 0 : Next(JSContext* aCx, JS::MutableHandle<JSObject*> aResult, ErrorResult& aRv)
83 : {
84 0 : JS::Rooted<JS::Value> value(aCx, JS::UndefinedValue());
85 0 : if (mIndex >= this->mIterableObj->GetIterableLength()) {
86 0 : DictReturn(aCx, aResult, true, value, aRv);
87 0 : return;
88 : }
89 0 : switch (mIteratorType) {
90 : case IterableIteratorType::Keys:
91 : {
92 0 : if (!ToJSValue(aCx, this->mIterableObj->GetKeyAtIndex(mIndex), &value)) {
93 0 : aRv.Throw(NS_ERROR_FAILURE);
94 0 : return;
95 : }
96 0 : DictReturn(aCx, aResult, false, value, aRv);
97 0 : break;
98 : }
99 : case IterableIteratorType::Values:
100 : {
101 0 : if (!ToJSValue(aCx, this->mIterableObj->GetValueAtIndex(mIndex), &value)) {
102 0 : aRv.Throw(NS_ERROR_FAILURE);
103 0 : return;
104 : }
105 0 : DictReturn(aCx, aResult, false, value, aRv);
106 0 : break;
107 : }
108 : case IterableIteratorType::Entries:
109 : {
110 0 : JS::Rooted<JS::Value> key(aCx);
111 0 : if (!ToJSValue(aCx, this->mIterableObj->GetKeyAtIndex(mIndex), &key)) {
112 0 : aRv.Throw(NS_ERROR_FAILURE);
113 0 : return;
114 : }
115 0 : if (!ToJSValue(aCx, this->mIterableObj->GetValueAtIndex(mIndex), &value)) {
116 0 : aRv.Throw(NS_ERROR_FAILURE);
117 0 : return;
118 : }
119 0 : KeyAndValueReturn(aCx, key, value, aResult, aRv);
120 0 : break;
121 : }
122 : default:
123 0 : MOZ_CRASH("Invalid iterator type!");
124 : }
125 0 : ++mIndex;
126 : }
127 :
128 : bool
129 0 : WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto, JS::MutableHandle<JSObject*> aObj)
130 : {
131 0 : return (*mWrapFunc)(aCx, this, aGivenProto, aObj);
132 : }
133 :
134 : protected:
135 : static void
136 0 : DictReturn(JSContext* aCx, JS::MutableHandle<JSObject*> aResult,
137 : bool aDone, JS::Handle<JS::Value> aValue, ErrorResult& aRv)
138 : {
139 0 : RootedDictionary<IterableKeyOrValueResult> dict(aCx);
140 0 : dict.mDone = aDone;
141 0 : dict.mValue = aValue;
142 0 : JS::Rooted<JS::Value> dictValue(aCx);
143 0 : if (!ToJSValue(aCx, dict, &dictValue)) {
144 0 : aRv.Throw(NS_ERROR_FAILURE);
145 0 : return;
146 : }
147 0 : aResult.set(&dictValue.toObject());
148 : }
149 :
150 : static void
151 0 : KeyAndValueReturn(JSContext* aCx, JS::Handle<JS::Value> aKey,
152 : JS::Handle<JS::Value> aValue,
153 : JS::MutableHandle<JSObject*> aResult, ErrorResult& aRv)
154 : {
155 0 : RootedDictionary<IterableKeyAndValueResult> dict(aCx);
156 0 : dict.mDone = false;
157 : // Dictionary values are a Sequence, which is a FallibleTArray, so we need
158 : // to check returns when appending.
159 0 : if (!dict.mValue.AppendElement(aKey, mozilla::fallible)) {
160 0 : aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
161 0 : return;
162 : }
163 0 : if (!dict.mValue.AppendElement(aValue, mozilla::fallible)) {
164 0 : aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
165 0 : return;
166 : }
167 0 : JS::Rooted<JS::Value> dictValue(aCx);
168 0 : if (!ToJSValue(aCx, dict, &dictValue)) {
169 0 : aRv.Throw(NS_ERROR_FAILURE);
170 0 : return;
171 : }
172 0 : aResult.set(&dictValue.toObject());
173 : }
174 :
175 : protected:
176 0 : virtual ~IterableIterator() {}
177 :
178 : // Since we're templated on a binding, we need to possibly CC it, but can't do
179 : // that through macros. So it happens here.
180 0 : virtual void UnlinkHelper() final
181 : {
182 0 : mIterableObj = nullptr;
183 0 : }
184 :
185 0 : virtual void TraverseHelper(nsCycleCollectionTraversalCallback& cb) override
186 : {
187 0 : IterableIterator<T>* tmp = this;
188 0 : NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mIterableObj);
189 0 : }
190 :
191 : // Binding Implementation object that we're iterating over.
192 : RefPtr<T> mIterableObj;
193 : // Tells whether this is a key, value, or entries iterator.
194 : IterableIteratorType mIteratorType;
195 : // Function pointer to binding-type-specific Wrap() call for this iterator.
196 : WrapFunc mWrapFunc;
197 : // Current index of iteration.
198 : uint32_t mIndex;
199 : };
200 :
201 : } // namespace dom
202 : } // namespace mozilla
203 :
204 : #endif // mozilla_dom_IterableIterator_h
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